#modprobe snd_aloop enable=1,1,1,1 index=1,2,3,4 pcm_substreams=1
modprobe snd_aloop pcm_substreams=1
Xvfb -ac :22
chromium --display=:22 --alsa-ouput-device="hw:Loopback,0,0" baidu.com
# .asoundrc
#pcm.!default { type plug slave.pcm "hw:Loopback,0,0" }
ffmpeg -f x11grab -i :22 -r 15 -f alsa -ac 2 -ar 44100 -i hw:Loopback,1,0 output.mp4


